network classifications local area network lan single room...

19
Local Area Net Technologies Ch. 13–17 (partial) Chapter 17 is chopped up and the pieces land in various places. · · 1 Packet Switching Instead of individual connections, data is sent in small pieces called packets. · · 2 Packets Larger transmissions are broken into multiple packets. A way of sharing a channel. Several senders generate packets. When the channel is available, a packet from any sender may go. As packets from different senders use the channel, the senders share the channel. The receiver can check each packet for correct transmission. · · 3 Network Classifications Local Area Network LAN Single room, building, or campus Metropolitan Area Network MAN Span a city Wide Area Network WAN Intercity or world-wide We’re starting with WANs · · 4

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Page 1: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Loca

lA

rea

Net

Tec

hnol

ogie

sC

h.

13–1

7(p

artial

)

Chap

ter

17is

chop

ped

up

and

the

pie

ces

land

inva

riou

spla

ces.

CS 423 ·TWBennet

·

MississippiCollege

1

Pack

et

Sw

itch

ing

Inst

ead

ofin

div

idual

connec

tion

s,dat

ais

sent

insm

allpie

ces

called

pack

ets.

CS 423 ·TWBennet

·

MississippiCollege

2

Pack

ets

Lar

ger

tran

smis

sion

sar

ebro

ken

into

multip

lepac

kets

.

Aw

ayof

shar

ing

ach

annel

.

Sev

eralse

nder

sge

ner

ate

pack

ets.

When

the

channel

isava

ilabl

e,a

pack

etfrom

any

sender

may

go.

As

pack

ets

from

diff

eren

tse

nder

suse

the

channel

,th

ese

nder

ssh

are

the

channel

.

The

rece

iver

can

chec

kea

chpac

ket

for

corr

ect

tran

smis

sion

.

CS 423 ·TWBennet

·MississippiCollege

3

Netw

ork

Cla

ssifi

cations

LocalA

rea

Netw

ork

LA

NSin

gle

room

,buildin

g,or

cam

pus

Metr

opolita

nA

rea

Netw

ork

MA

NSpan

aci

ty

Wid

eA

rea

Netw

ork

WA

NIn

terc

ity

orw

orld

-wid

e

We’

rest

art

ing

with

WA

Ns

CS 423 ·TWBennet

·

MississippiCollege

4

Page 2: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Sta

ndard

sB

odie

s

Spec

ialize

indiff

eren

tar

eas.

And

IET

Fis

quite

act

ive

attransp

ort

,also

CS 423 ·TWBennet

·

MississippiCollege

5

IEEE

LA

NSta

ndard

s

802.

3C

SM

A/C

D(E

ther

net

)

802.

5Tok

enR

ing

802.

11W

irel

ess

LA

N

802.

16W

irel

ess

Bro

adban

d

Man

yot

her

s.

CS 423 ·TWBennet

·

MississippiCollege

6

IEEE

LA

NSta

ndard

s

Tw

opar

ts:

LLC

and

MA

C

LLC

:Logic

allink

contr

ol

Addre

ssin

gan

ddem

ultip

lexin

gD

emultip

lexi

ng

most

lym

eans

iden

tify

ing

whatea

chpa

cket

isfo

r.

MA

C:M

edia

Access

Contr

ol

How

hos

tssh

are

aco

mm

onm

ediu

mLots

ofhost

s,one

wire

or

freq

uen

cy.

CS 423 ·TWBennet

·MississippiCollege

7

LA

NTopolo

gie

s

Apoi

nt-

to-p

oint

link

connec

tstw

oco

mpute

rs.

Poi

nt-

to-p

oint

links

bet

wee

nea

chco

mpute

rar

eto

oex

pen

sive

.

Connec

ting

nco

mpute

rsre

quires

n2−

n2

links

.

LA

Ns

use

dsh

ared

connec

tion

s.

CS 423 ·TWBennet

·

MississippiCollege

8

Page 3: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

IEEE

MA

CA

ddre

ssin

g

Eac

had

dre

ssis

48bits.

Eac

hac

cess

card

ism

anufa

cture

dw

ith

auniq

ue

idad

dre

ss.

Hig

hbit

iden

tifies

spec

ialad

dre

sses

.

Top

thre

ebyte

sis

aco

de

for

the

man

ufa

cture

rA

ssig

ned

byIE

EE.

Top

bitis

zero

.

Org

aniz

atio

nal

lyU

niq

ue

ID(O

UI)

Eac

hor

ganiz

atio

nm

akes

the

bal

ance

uniq

ue

for

each

dev

ice

itse

lls.

CS 423 ·TWBennet

·

MississippiCollege

9

Delivery

The

shar

edm

ediu

mca

rrie

sea

chpac

ket

toea

chst

atio

n.

When

ast

atio

nge

tsa

pac

ket

addre

ssed

toA

:

Ifhig

hbit(A

)is

zero

,an

dit

mat

ches

my

addre

ss,ke

epit.

Els

eif

Ais

FF:F

F:F

F:F

F:F

F:F

F(t

he

bro

adca

stad

dre

ss),ke

epth

em

essa

ge.

Els

eif

hig

hbit(A

)is

one,

and

Am

atch

esa

multic

ast

addre

ssin

my

rece

ive

list

,ke

epth

em

essa

ge.

Els

edro

pth

em

essa

ge.

This

allo

ws

effici

ent

bro

adca

st,m

ultic

ast

and

poi

nt-

to-p

oint.

CS 423 ·TWBennet

·

MississippiCollege

10

LA

NTopolo

gie

s

The

dia

gram

des

cribes

elec

tricalco

nnec

tion,

notnec

essa

rily

appe

ara

nce

.

CS 423 ·TWBennet

·MississippiCollege

11

Fra

me

Form

at

Hea

der

conta

ins

addre

ssin

gan

der

ror

chec

kor

corr

ection

dat

a.

Hea

der

isusu

ally

atfr

ont,

may

be

atei

ther

end,

orm

ayev

enbe

split.

Pre

lude

and

pos

tlude

incl

ude

mar

kers

and

clock

synch

roniz

atio

n.

CS 423 ·TWBennet

·

MississippiCollege

12

Page 4: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Suppose

We

Use

AM

ark

er

Byte

Tw

odiff

eren

tch

arac

ters

are

safe

rth

ana

singl

em

arke

rin

case

ofco

rrupt

tran

smis

sion

.

CS 423 ·TWBennet

·

MississippiCollege

13

Byte

Stu

ffing

When

you

nee

dto

send

am

arke

ras

dat

a.

CS 423 ·TWBennet

·

MississippiCollege

14

4B

/5B

Codin

g

An

alter

native

use

din

fibe

roptic

LA

Ns

4B/5

Bco

din

gsc

hem

ese

nds

dat

ain

5-bit

units.

Eac

hunit

repre

sents

eith

er:

•Fou

rbits

ofdat

a(o

ne

ofth

e16

4-bit

pat

tern

s).

•A

contr

olco

de.

CS 423 ·TWBennet

·MississippiCollege

15

4B

/5B

Som

eofth

e4B/5B

codes

Code

Meanin

g

0110

1T

Con

trol

(Par

tof

end

del

imiter

)

0111

0D

ata

0110

0111

1D

ata

0111

1000

0U

nuse

d

1000

1K

Con

trol

(Par

tof

star

tdel

imiter

)

1001

0D

ata

1000

When

each

five

-bit

unit

arri

ve,it

isei

ther

four

byte

sof

dat

aor

aco

ntr

olco

de.

No

nee

dfo

res

cape

codes

.

CS 423 ·TWBennet

·

MississippiCollege

16

Page 5: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

IEEE

MA

CSubla

yer

Multi-A

ccess

Pro

tocols

Con

trol

led

Acc

ess

Pro

toco

lsR

eser

vation

Pol

ling

Tok

enPas

sing

Ran

dom

Acc

ess

Pro

toco

lsA

loha

CSM

A/C

DC

SM

A/C

A

Chan

nel

izat

ion

Pro

toco

lsFD

MA

TD

MA

CD

MA

CS 423 ·TWBennet

·

MississippiCollege

17

Channelization

Pro

tocols

Thes

ear

eth

ety

pes

ofm

ultip

lexin

g,as

cove

red

earl

ier.

FD

MA

=Fre

quen

cy-D

ivis

ion

Multip

leA

cces

sT

DM

A=

Tim

e...

CD

MA

=C

ode.

..

Ass

ign

chan

nel

sw

ith

aco

ntr

olch

annel

and

centr

alar

biter

.

CS 423 ·TWBennet

·

MississippiCollege

18

Contr

olled

Access

Pro

tocols

Thes

eare

all

form

softim

em

ultip

lexi

ng

Pollin

gA

contr

olst

atio

ns

gran

tsea

chre

gula

rst

atio

nper

mis

sion

tose

nd.

May

use

round-r

obin

orpri

ority

order

.

Rese

rvation

Sim

ilar

toro

und-r

obin

,ex

cept

stat

ions

ask

tobe

added

toth

ero

tation

when

the

hav

eso

met

hin

gto

send.

Typic

alfo

rsa

tellite

tran

smis

sion

.

CS 423 ·TWBennet

·MississippiCollege

19

Contr

olled

Access

Pro

tocols

(Cont)

Token

Pass

ing

Asi

ngl

eci

rcula

ting

toke

nre

pre

sents

per

mis

sion

tose

nd.

Pop

ula

ron

wir

edLA

Ns

inth

epas

t;ra

renow

.

Par

tof

FD

DI

for

optica

lLA

Ns.

CS 423 ·TWBennet

·

MississippiCollege

20

Page 6: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Random

Access

Pro

tocols

This

grou

pof

pro

toco

lsav

oid

the

nee

dfo

ran

yce

ntr

alco

ordin

atio

n.

The

gener

alru

leis

:go

ahea

dan

dtr

y.If

itfa

ils,

try

agai

nla

ter.

Coor

din

atio

nis

loca

l,dis

trib

ute

d,an

dof

ten

afte

r-th

e-fa

ct.

The

nam

ese

ems

tosign

ify

the

fact

thatse

nder

sst

art

sendin

gwhen

ever

they

wish.

CS 423 ·TWBennet

·

MississippiCollege

21

Alo

ha

The

histo

ric

pre

dec

esso

rofth

eoth

erRandom

Acc

ess

pro

toco

ls.

Only

the

centr

alto

wer

sends

onth

eou

tbou

nd

freq

uen

cy.

Itre

pea

tsm

essa

ges

from

outlyin

gst

atio

ns

for

all.

Any

stat

ion

can

send

toal

lw

ith

the

centr

alre

lay.

CS 423 ·TWBennet

·

MississippiCollege

22

Alo

ha

Outlyin

gst

atio

ns

send

when

ever

they

like

.

What

iftw

ose

nd

atth

esa

me

tim

e?C

ombin

atio

nm

essa

geis

garb

led.

Chec

ksu

mfa

ils.

Mes

sage

isdis

card

ed.

An

outlyin

gse

nder

list

ens

for

the

repea

tof

its

own

pac

ket.

Ifit

does

not

see

its

mes

sage

com

ing

bac

k,re

send.

Eac

hm

ust

wai

ta

diff

eren

tam

ount

oftim

ebef

ore

rese

ndin

g.O

ther

wis

e,an

other

collis

ion

They

each

choos

ea

random

amou

nt

oftim

eto

wai

t.A

lmos

tce

rtai

nly

willdiff

er.

CS 423 ·TWBennet

·MississippiCollege

23

CSM

A/C

D(E

thern

et)

Car

rier

Sen

seon

Multip

leA

cces

sw

ith

Col

lisi

onD

etec

tion

•W

ait

for

sile

nce

bef

ore

sendin

ga

fram

e(C

arr

ier

sense

)

•W

hile

sendin

g,se

eth

atth

esi

gnal

onth

ebus

mat

ches

what

isbei

ng

sent.

(Collisio

nD

etec

tion)

•If

not

,st

op.

•Try

agai

na

random

tim

ela

ter.

•For

each

re-s

end

collis

ion,dou

ble

the

range

from

whic

hth

era

ndom

del

ayis

chos

en.

CS 423 ·TWBennet

·

MississippiCollege

24

Page 7: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Bin

ary

ExponentialB

ack

-off

The

random

del

ayis

chos

enfr

oma

range

.

On

each

repea

ted

collis

ion,th

era

nge

isdou

ble

d.

Dou

bling

the

range

each

tim

ehal

ves

the

pro

bab

ility

ofa

new

collis

ion.

Mor

eim

por

tantly,

itsl

ows

and

scat

ters

sender

sw

hen

the

net

isbusy

.

CS 423 ·TWBennet

·

MississippiCollege

25

Wir

ele

ss

Con

sider

thre

eco

mpute

rsat

the

max

imum

dis

tance

:

Apac

ket

sent

ona

wir

eles

sLA

Nm

aynot

reac

hal

lst

atio

ns.

Com

pute

rs1

and

3m

ayse

nd

to2

atth

esa

me

tim

e.

Com

pute

r2

willse

ea

collis

ion

and

dis

card

.

Com

pute

rs1

and

3w

illth

ink

the

pac

ket

mad

eit.

CS 423 ·TWBennet

·

MississippiCollege

26

CSM

A/C

A

For

wirel

ess

CA

=C

ollisi

onA

void

ance

.

•Sen

da

contr

olm

essa

geto

the

inte

nded

reci

pie

nt.

Wai

tfo

ra

reply

.

•W

hen

are

ply

isre

ceiv

ed,se

nd

dat

a.

•In

case

ofa

collis

ion,th

ere

cipie

nt

willnot

answ

er.

•Sen

der

sw

illth

endel

ayan

dre

-sen

d,as

CSM

A/C

D.

Collisio

ns

are

det

ecte

dby

the

reci

pie

ntra

ther

than

the

sender

.

CS 423 ·TWBennet

·MississippiCollege

27

CSM

A/C

A

CS 423 ·TWBennet

·

MississippiCollege

28

Page 8: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Eth

ern

et

CSM

A/C

Don

ash

ared

wir

e.

Pac

ket

form

at

Fie

ldsi

zes

are

inbyte

s.

Notice

thatth

ere

isa

min

imum

payl

oad

size

.

CS 423 ·TWBennet

·

MississippiCollege

29

Eth

ern

et

Fra

me

Fie

lds

Eac

hst

atio

nhas

a6-

byte

IEE

EM

AC

addre

ss.

Sou

rce

and

des

tinat

ion

carr

ied

onea

chpac

ket.

Eac

hfr

ame

has

atw

o-byte

type

iden

tifier

.Tel

lsth

ere

ceiv

erhow

toin

terp

ret

the

pay

load

.

Pre

amble

isal

tern

atin

g1’

san

d0’

s,but

endin

gw

ith

11,to

synch

roniz

eth

ere

ceiv

er.

CS 423 ·TWBennet

·

MississippiCollege

30

Fra

me

Type

Exam

ple

s

Ther

ear

em

any.

Her

ear

ea

few

sam

ple

s.

0800

IP

6004

DE

CLA

T

805C

Sta

nfo

rdV

Ker

nel

80D

5IB

MSN

A

8137

-8N

ovel

lIP

X

CS 423 ·TWBennet

·MississippiCollege

31

IEEE

802.3

Abov

eis

the

mos

tco

mm

onfo

rmat

,E

ther

net

II.

IEE

Eex

pan

ded

itto

add

additio

nal

way

sof

iden

tify

ing

dat

a.

Ifth

ety

pe

is<

1500

,it

isa

pac

ket

lengt

h,an

dth

enex

t3

byte

sis

aLog

ical

Lin

kC

ontr

ol(L

LC

)hea

der

.

The

firs

ttw

oLLC

byte

sar

eD

SA

P(D

estinat

ion

Ser

vic

eA

cces

sPoi

nt)

and

SSA

P(S

ourc

eSA

P).

The

thir

dis

aLLC

type

code

(“co

ntr

olbyte

”).

The

CSA

Pan

dD

SA

Par

eju

stm

ore

type

codes

.T

hough

the

sourc

eand

des

tination

type

sca

ndiff

er.

For

inst

ance

,IP

isSA

Pco

de

06;N

ove

llis

E0

CS 423 ·TWBennet

·

MississippiCollege

32

Page 9: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

IEEE

802.3

(continued)

But,

wai

t!T

her

e’s

more

!

Ifth

eLLC

code

isA

AA

A03

,th

eLLC

isfo

llow

edby

a5-

byte

Sub-N

etw

ork

Att

achm

ent

Poi

nt

(SN

AP

)co

de.

SN

AP

isth

ree

byte

sof

orga

niz

atio

nco

de

(OU

I)an

da

two

byte

type

code.

This

allows

org

anizations

tosp

ecify

thei

rown

pro

pri

etary

type

codes

.

Extr

afiel

ds

subtr

act

from

the

max

imum

pay

load

size

,ke

epin

gth

em

axim

um

pac

ket

size

unch

ange

d.

CS 423 ·TWBennet

·

MississippiCollege

33

Netw

ork

Inte

rface

Contr

oller

Hard

ware

Inte

rnal

Bus

NIC

Net

wor

k

AN

ICtr

ansf

ers

pac

kets

bet

wee

nth

enet

wor

kan

dsy

stem

bus.

NIC

inte

rrupts

the

CP

Uw

hen

itnee

ds

topro

cess

apac

ket.

May

be

ase

par

ate

expan

sion

card

.N

owad

ays,

Mos

tP

Cm

other

boa

rds

inte

grat

ea

NIC

.

CS 423 ·TWBennet

·

MississippiCollege

34

NIC

Continued

The

NIC

reliev

esth

eC

PU

ofse

vera

lta

sks.

Han

dle

sth

elo

w-lev

elpro

toto

clru

les

tose

nd

and

rece

ive.

Such

as

CSM

A/C

Dfo

rEth

ernet

.

Chec

ks

inbou

nd

addre

sses

and

dis

card

spac

kets

whic

har

enot

for

us.

Ver

ifies

CR

Cs

onin

bou

nd

pac

kets

and

com

pute

sth

emfo

rou

tbou

nd.

CS 423 ·TWBennet

·MississippiCollege

35

Earl

yEth

ern

et

Thic

k-W

ire

(coa

x)

Thin

-Wir

e(c

oax)

CS 423 ·TWBennet

·

MississippiCollege

36

Page 10: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Tw

iste

d-P

air

Eth

ern

et

Tw

iste

dpai

r.

Elect

rica

lly

abu

s,ev

enth

ough

itlo

oks

like

ahub

and

spoke

s.

When

ahos

tse

nds

am

essa

ge,th

ehub

repea

tsit

toth

eot

her

s.

CS 423 ·TWBennet

·

MississippiCollege

37

Eth

ern

et

Gets

Tw

iste

d

Ori

ginal

Eth

ernet

cable

had

asi

ngl

ech

annel

.C

able

sfo

rT

PE

ther

net

conta

inw

ires

enou

ghfo

rtw

o.

Cab

leis

only

connec

ted

ontw

oen

ds.

Eac

hen

dhas

one

chan

nel

toitse

lffo

rse

ndin

g.

Cap

acity

ispot

ential

lydou

ble

d.

CS 423 ·TWBennet

·

MississippiCollege

38

Bri

dges

Abri

dge

connec

tstw

oLA

Nse

gmen

tsan

dfo

rwar

ds

traffi

cea

chw

ay.

CS 423 ·TWBennet

·MississippiCollege

39

Learn

ing

Bri

dges

Watc

htraffi

cto

see

wher

ehost

sare

.

Kee

ps

alist

ofhar

dw

are

addre

sses

,w

ith

the

segm

ent

each

ison

.T

his

list

isin

itia

lly

empty

.

When

any

pac

ket

isse

en,its

sourc

ead

dre

ssan

dth

ese

gmen

tth

epac

ket

arri

ved

onar

ead

ded

toth

eta

ble

.

When

apac

ket

des

tined

for

xar

rive

s:•

Ifx

isin

the

table

,fo

rwar

dor

not

asap

pro

pri

ate.

•If

xis

not

inth

eta

ble

,fo

rwar

dth

epac

ket.

Eve

ntu

ally

the

table

fills

up

and

unnec

essa

ryfo

rwar

din

gen

ds.

CS 423 ·TWBennet

·

MississippiCollege

40

Page 11: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Eth

ern

et

Sw

itch

es

Eth

ernet

hubs

hav

ela

rgel

ygi

ven

way

tosw

itch

es.

The

switch

acts

like

aco

llec

tion

ofle

arnin

gbri

dge

s.

CS 423 ·TWBennet

·

MississippiCollege

41

Eth

ern

et

Sw

itch

es

Sw

itch

esw

illnot

send

two

mes

sage

sto

the

sam

ehos

tat

atim

e.

Hos

tsw

on’t

see

mes

sage

sbou

nd

for

other

s.

When

switch

esre

pla

ceal

lhubs,

the

syst

emis

esse

ntial

lyco

llis

ion-fre

e.

Sec

uri

tyis

also

impro

ved

since

much

less

thir

d-p

arty

traffi

cis

acce

ssib

leto

snoop

ing

athos

ts.

CS 423 ·TWBennet

·

MississippiCollege

42

VLA

NSw

itch

es

Asi

ngl

esw

itch

whic

hca

nbeh

ave

asm

ultip

lesw

itch

es.

The

adm

inis

trat

orco

nfigu

res

itto

crea

teth

evir

tual

switch

es.

Eac

hvir

tual

switch

form

sa

vir

tual

LA

N.

Mai

npurp

ose

isto

crea

tein

tern

alfire

wal

ls.

Bro

adca

stand

multicast

traffi

cdoe

snotpa

ssbe

twee

nvi

rtual

switch

es.

The

vir

tual

LA

Ns

may

then

be

connec

ted

by

afire

wal

lto

contr

olex

chan

ge.

CS 423 ·TWBennet

·MississippiCollege

43

Wir

ele

ss

LA

Ns,

MA

Ns

orW

AN

s

PA

Ns

Per

sonal

Are

aN

etw

orks

Syn

cing

dev

ices

Blu

etoot

hIn

fraR

edIS

Mw

irel

ess

CS 423 ·TWBennet

·

MississippiCollege

44

Page 12: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

ISM

Bands

Indust

rial

,Sci

entific,

Med

ical

Not

lice

nce

dto

spec

ific

use

rs.

CS 423 ·TWBennet

·

MississippiCollege

45

Wir

ele

ssSta

ndard

s

802.

112.

4G

Hz

1or

2M

bps

802.

11a

5.72

5G

Hz

6–54

Mbps

802.

11b

2.4

GH

z5.

5or

11M

bps

802.

11g

2.4

GH

z22

or54

Mbps

Man

yot

her

s.

CS 423 ·TWBennet

·

MississippiCollege

46

Wir

ele

ssN

etw

ork

Types

Ad

Hoc

Any

two

nod

esca

nco

mm

unicate

.R

arel

yuse

d

Infr

astr

uct

ure

Nod

esta

lkto

an

acc

ess

poin

t.Acc

ess

poin

tfo

rward

sall

com

munications.

The

nodes

anac

cess

poi

nt

com

munic

ates

with

isa

Bas

icSer

vic

eSet

(BSS).

CS 423 ·TWBennet

·MississippiCollege

47

Access

Poin

ts

CS 423 ·TWBennet

·

MississippiCollege

48

Page 13: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Talk

ing

To

Your

Access

Poin

t

May

be

dea

dzo

nes

bet

wee

nac

cess

poi

nts

.

Am

obile

hos

tm

ayse

ese

vera

lac

cess

poi

nts

.

Inin

fras

truct

ure

mode,

hos

tsm

ust

ass

ocia

tew

ith

anac

cess

poi

nt.

Fir

stac

cess

poi

nts

had

com

ple

xhan

d-o

fffa

cilities

Lik

ece

llphone

tower

s.

Curr

ent

pra

ctic

eis

tole

tth

em

obile

hos

tw

orry

abou

tit.

Pro

toco

lal

low

sa

conte

ntion

-fre

em

ode

wher

eth

eA

Pas

sign

sdiff

eren

tfr

equen

cies

.Rare

lyuse

d

CS 423 ·TWBennet

·

MississippiCollege

49

802.1

1Fra

me

Form

at

CT

Lin

cludes

pro

toco

lan

dfr

ame

type

codes

,an

dva

riou

sflag

s.

DU

Rhas

multip

leuse

sre

late

dto

tim

eout

sett

ing

and

gett

ing

mes

sage

sth

atar

rive

dw

hile

you

wer

eas

leep

.

SE

Qis

use

dto

iden

tify

duplica

tefr

ames

and

collec

tpar

tsof

afr

agm

ente

dfr

ame

CS 423 ·TWBennet

·

MississippiCollege

50

WiM

AX

IEE

E80

2.16

Des

igned

topro

vid

ew

irel

ess

last

-mile

bro

adban

d.

Noten

tire

lyco

oke

dye

t.

Can

use

lice

nce

dor

non

-lic

ence

dfr

equen

cies

.P

rim

arily

lice

nce

d.

Pro

vid

estw

oty

pes

oflinks

CS 423 ·TWBennet

·MississippiCollege

51

WiM

AX

(cont)

Hig

h-b

andw

idth

tow

er-t

o-to

wer

line-

of-s

ight

back

haul

Use

shig

her

freq

uen

cies

Low

-ban

dw

idth

tow

erto

use

rN

otline-

of-s

ight;

pas

sth

rough

obst

acle

s.

Use

sfr

equen

cies

sim

ilar

toW

iFi.

CS 423 ·TWBennet

·

MississippiCollege

52

Page 14: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

WiM

AX

CS 423 ·TWBennet

·

MississippiCollege

53

Last

Lin

k

Bot

hfixed

and

mob

ile

vers

ions.

Fix

edve

rsio

nuse

sa

par

abol

ican

tenna

Mob

ile

vers

ion

has

tow

erhan

d-o

fflike

ace

llphon

e.

CS 423 ·TWBennet

·

MississippiCollege

54

Ort

hogonalFre

quency

Div

isio

nM

ultip

lexin

g

Use

multip

leca

rrie

rsto

get

mor

eban

dw

idth

.

Use

ban

ds

that

actu

ally

over

lap.

Inst

ead

ofgu

ard

ban

ds,

ort

hog

onalca

rrie

rsar

ech

osen

.

Ort

hog

onal

carr

iers

add

up

toze

ro.

This

mea

ns

cros

s-ch

annel

inte

rfer

ence

adds

up

toze

ro.

Pac

km

ore

chan

nel

sin

toa

give

nban

dw

idth

.

CS 423 ·TWBennet

·MississippiCollege

55

PA

NTech

nolo

gie

s

Blu

etoot

h,80

2.15

.1a

Rep

lace

men

tfo

rw

ire

connec

tion

s:m

ouse

,hea

dphon

es.

2.4G

Hz

5m72

1Kbps

Mas

ter

gran

tsper

mis

sion

tosl

ave

Ultra

Wid

eban

d,80

2.15

.3a

Multip

lefr

equen

cies

2–10

m50

0–11

0Mbps

Goes

thro

ugh

wal

lsN

osi

ngl

est

andar

d.

CS 423 ·TWBennet

·

MississippiCollege

56

Page 15: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

PA

N,C

ont.

Zig

bee

,80

2.15

.4Sta

ndar

diz

ere

mot

eco

ntr

ols

Spee

dnot

apri

ority

868M

Hz,

915M

Hz,

2.4G

Hz

−→

20M

Hz,

40M

Hz,

250M

Hz

Low

pow

er

CS 423 ·TWBennet

·

MississippiCollege

57

Oth

er

Short

-Dis

tance

IrD

A(I

nfr

ared

)Fam

ily

ofst

andar

ds

Few

met

ers

30-d

egre

eco

ne

2.4K

bps

or16

Mbps

RFID

Rad

ioFre

quen

cyId

entifica

tion

Ove

r14

0va

riou

sst

andar

ds

100M

Hz–

954M

Hz

Pas

sive

orac

tive

Inve

nto

ryco

ntr

olal

tern

ativ

eto

swip

eca

rds.

CS 423 ·TWBennet

·

MississippiCollege

58

Cellula

rSyst

em

s

Des

igned

for

voic

eD

ata

Wor

ks

fine

CS 423 ·TWBennet

·MississippiCollege

59

Cellula

rSyst

em

s

Fre

quen

cies

are

chos

enso

nei

ghbor

sal

way

sdiff

er.

CS 423 ·TWBennet

·

MississippiCollege

60

Page 16: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Genera

tions

1GA

nal

ogvo

ice

sign

al.

2GD

igital

sign

als

toca

rry

voic

e.

3GD

ata

dow

nlo

adfo

rbro

wsi

ng;

inte

roper

ability.

4GM

ultim

edia

.

CS 423 ·TWBennet

·

MississippiCollege

61

Sate

llite

Ear

lygr

ound

stat

ions

nee

ded

larg

edis

ks.

For

hom

es,V

ery

Sm

allA

per

ture

Ter

min

al(V

SA

T)

Var

ious

freq

uen

cies

.

CS 423 ·TWBennet

·

MississippiCollege

62

Cycle

sIn

The

Net

Abro

adca

stpac

ket

willgo

onfo

reve

r.

Lea

rnin

gpro

ble

ms:

IfB

1fo

rward

sa

pack

etfrom

segm

enta

tob,

then

B3

willth

ink

its

sourc

eis

on

segm

entb,

and

forw

ard

traffi

cunnec

essa

rily

.

CS 423 ·TWBennet

·MississippiCollege

63

Avoid

ing

The

Cycle

s

Dis

trib

ute

dSpan

nin

gTre

e

Com

pute

asu

bgr

aph

ofex

isting

connec

tion

sfo

rmin

ga

span

nin

gtr

ee.

Acy

clic

and

reach

esall

route

rs.

Must

wor

kev

enth

ough

no

one

know

show

the

net

isar

range

d.

CS 423 ·TWBennet

·

MississippiCollege

64

Page 17: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

What

The

Alg

ori

thm

Dete

rmin

es

One

route

ris

des

ignat

edth

ero

ot.

Eac

hpor

ton

each

route

ris

clas

sified

root

,des

ignat

ed,or

blo

ckin

g.

The

root

por

tis

the

quic

kest

way

from

the

route

rto

the

root

.

Ades

ignat

edpor

tis

the

quic

kest

way

for

the

atta

ched

net

wor

kto

reac

hth

ero

ot.

Blo

ckin

gpor

tsar

enot

par

tof

the

tree

.

Tra

ffic

isfo

rwar

ded

thro

ugh

des

ignat

edan

dro

otpor

ts.

This

use

son

lyan

acycl

icsu

bse

tof

the

actu

alco

nnec

tion

s.

CS 423 ·TWBennet

·

MississippiCollege

65

Com

puting

The

Tre

e

The

root

issi

mply

the

route

rw

ith

the

low

est

MA

Cad

dre

ss.

Eac

hbri

dge

has

anid

eaof

who

the

root

is,th

eco

stto

get

ther

e,an

dw

hic

hpor

tto

send

on.

Initia

lly,

itis

us

with

zero

cost

.

The

bri

dge

per

iodic

ally

sends

this

info

rmat

ion

toits

nei

ghbor

s.

Eac

hpor

tke

eps

trac

kof

the

bes

tof

thes

em

essa

ges

ithas

seen

,an

dw

ho

sent

it.

CS 423 ·TWBennet

·

MississippiCollege

66

How

To

Get

There

best[p]is

the

bes

tm

essa

gese

enon

por

tp.

toroot

isth

ero

ot,co

st,an

dse

ndin

gpor

tfo

rth

ebes

tro

ute

toth

ero

ot.

Upon

rece

ipt

ofa

mes

sage

(root,

cost)

from

bri

dge

b

arri

vin

gon

por

tp:

If(r

oot,

cost)

<be

st[p],

then

best[p]:=

(root,

cost)

If[r

oot,

cost+

arc]

<(t

oroot.root,

toroot.co

st)

,th

en

toroot:=

(root,

cost+

arc,

p).

Wher

earc

isth

eco

stfo

rse

ndin

gto

b.

CS 423 ·TWBennet

·MississippiCollege

67

Desi

gnate

dPort

s

Any

non

-root

por

tw

hos

eco

stis

hig

her

than

the

bri

dge

s’s

root

cost

isa

des

ignat

edpor

t.

This

ispo

ssib

lebe

cause

ofaddin

gth

elink

befo

rech

oosing

the

brid

ge’s

cost

.

This

isri

ghtbe

cause

itm

eans

this

port

offer

sa

chea

per

path

toth

ero

otth

an

any

ofth

eoth

erbr

idge

sattach

edher

e.

Tie

sare

broke

nby

com

pari

ng

our

route

rnum

ber

toth

eso

urc

eofth

em

atc

hin

gco

st.

Any

por

tot

her

than

root

ordes

ignat

edis

blo

cked

.M

essa

ges

are

not

forw

arded

thro

ugh

it.

CS 423 ·TWBennet

·

MississippiCollege

68

Page 18: Network Classifications Local Area Network LAN Single room ...sandbox.mc.edu/~bennet/cs423v2/slides5/lan-4.pdf · Network Classifications Local Area Network LAN Single room, building,

Additio

nalD

eta

ils

Alg

orithm

runs

continuou

sly

soth

enet

adap

tsto

chan

ges.

All

sort

sof

del

ays,

det

ailru

les

and

lim

its

toav

oid

tem

por

ary

cycl

es.

Adm

inis

trat

ors

can

modify

order

ing

with

wei

ghts

.D

eter

min

eth

ero

otby

wei

ghting

oth

erbo

xes.

Wei

ghta

port

todisco

ura

geits

use

.

Lin

kco

sts

are

set

by

adm

inis

trat

or.

Def

aults

bas

edon

link

spee

d.

CS 423 ·TWBennet

·

MississippiCollege

69

AC

ycling

Tri

p

CS 423 ·TWBennet

·

MississippiCollege

70

Sourc

es

Com

er,C

om

pute

rN

etwork

sand

Inte

rnet

s(O

ur

belo

ved

text

book.

)

For

ouza

n,D

ata

Com

munications

and

Net

work

ing,

McG

raw

-Hill,

2001

.

Subnet

wor

kA

cces

sP

roto

colar

ticl

efr

omW

ikip

edia

htt

p:/

/ww

w.w

ildpac

kets

.com

/suppor

t/co

mpen

diu

m/-

ether

net

/fra

me

form

ats

htt

p:/

/ww

w.g

eoci

ties

.com

/Silic

onV

alle

y/H

aven

/-48

24/e

ther

net

.htm

l

htt

p:/

/wifi

.cs.

st-a

ndre

ws.

ac.u

k/w

ififr

ame.

htm

l

CS 423 ·TWBennet

·MississippiCollege

71

Sourc

es,

Cont.

htt

p:/

/tec

hnet

.mic

roso

ft.c

om/e

n-u

s/libra

ry/c

c757

419.

asp

x

htt

p:/

/ww

w.h

owst

uffw

orks.

com

/wim

ax1.h

tm

htt

p:/

/ww

w.c

reat

e.ucs

b.e

du/A

TO

N/0

1.01

/OFD

M.p

df

htt

p:/

/ww

w.c

is.tem

ple

.edu/

inga

r-gi

o/ol

d/c

is30

7f98

/rea

din

gs/b

ridge

.htm

l

htt

p:/

/ww

w.e

ther

man

age.

com

/eth

ernet

/100

quic

kre

f/-

ch13

qr

4.htm

l

htt

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